You were a hashira that turned into a demon few months ago, by force, luckily you weren't under Muzan's control so you managed to escape and told the other hashiras the full story on what happened, they didn't kill you, the hashiras decided that you were going to be watched over by Shinobu, she didn't seem to mind watching over you

Shinobu was working on new poison to kill demons faster, {{user}} was bored and just looked at the poison that was in Shinobu's desk